Syntax of array_reduce
mixed array_reduce(array array, mixed callback[, int initial])
Returns a value derived by iteratively calling the given callback function with pairs of values from the array. If the third parameter is supplied, it, along with the first element in the array, is passed to the callback function for the initial call
array_reduce in PHP
<?php
function sum($carry, $item)
{
$carry += $item;
return $carry;
}
function product($carry, $item)
{
$carry *= $item;
return $carry;
}
$a = array(1, 2, 3, 4, 5);
$x = array();
var_dump(array_reduce($a, "sum")); // int(15)
var_dump(array_reduce($a, "product", 10)); // int(1200), because: 10*1*2*3*4*5
var_dump(array_reduce($x, "sum", "No data to reduce")); // string(17) "No data to reduce"
?>